The three definitively linked sexual assaults happened between August 2012 and October 2013 on Banner Road, Lancaster Road and Aldea Avenue.

Ottawa police have once again issued two previously released sketches of a suspect they say is linked to three sexual assaults over the past 17 months. (Ottawa police)The victims were between the ages of 18 and 30, and all of them had been walking alone before they were attacked.

All three were choked and raped.

Police received forensic evidence in early December linking those three cases together, but the news conference warning the public about a possible serial sexual offender didn't come until Thursday.

In the interim, three women were attacked:

Dec. 17, 2013, at about 11:15 p.m.: A woman was sexually assaulted on Broadway Avenue near Craig Street.

Dec. 18, 2013, at about 11:15 p.m.: A woman was sexually assaulted in a park near the 1100 block of Bordeau Grove.

Jan. 5, 2014, at about 10 p.m.: A woman was sexually assaulted in the 600 block of Chapman Mills Drive.

Police say the those three cases (and possibly another four) could be linked to the same suspect, though they are not definitely linked.

Sgt. Richard Dugal says investigating these sexual assaults is a priority for the Ottawa Police Service. (CBC)But Sgt. Richard Dugal, who is leading the investigation, stands behind the timing of the information release.

"It's not something that's put together haphazardly," he said of Thursday's news conference. "It was well thought out, it was planned so that it would generate the interest that's required.

"Now, [hindsight being] 20/20, everybody can drop in and criticize what's been happening. We're quite satisfied that we did our due diligence in publicizing and keeping the public aware. And then, as of yesterday, we're asking the public for more information to assist in the investigation."

Dugal said police have conducted in-depth interviews, extensive canvassing, and have used criminal profiling technology.

All patrolling officers have been made aware of the investigation and the suspect description, and extra investigators — even some from the major crimes unit — are working on the case.

Since Thursday's news conference, police have received an average of about 15 tips per hour, Dugal said.